In a Long Term Evolution (LTE) standard and a Long Term Evolution-Advanced (LTE-A) standard, a system frame of Time Division Duplexing (TDD) LTE is composed of ten sub-frames. A 3rd Generation Partnership Project (3GPP) supports seven kinds of frame structures in total, as shown in FIG. 1, wherein D represents a downlink channel sub-frame, S represents a shared channel sub-frame, and U represents an uplink channel sub-frame.
SwitchingUplink andpointdownlinkperiodframefromstructuredownlinkSub-frame numbernumberto uplink012345678905 msDSUUUDSUUU15 msDSUUDDSUUD25 msDSUDDDSUDD310 ms DSUUUDDDDD410 ms DSUUDDDDDD510 ms DSUDDDDDDD65 msDSUUUDSUUD
Currently, in a 3GPP standard, a User Equipment (UE) is informed of the frame structure configured for a current serving cell via a system information block (SIB-I). In a pre-research project of “a dynamic TDD frame structure” formally approved by a RAN54th (December, 2011) plenary meeting of the 3GPP, dynamically allocating the frame structure of a TDD LTE system becomes more possible. However, a minimum varying period of SIB information according to an existing 3GPP standard is 640 ms, and the frame structure of the TDD LTE system cannot be dynamically allocated in time. How to shorten the varying period of the frame structure of the TDD LTE system, and to more dynamically inform R11 and a subsequent version of UE of the frame structure employed by a next configuration period in a condition that 3GPP R8˜R10 is compatible, does not have a corresponding solution currently.
In an invention patent of which the application number is 201210030111.8, disclosed is a method for notifying the UE of the frame structure employed by the next configuration period by using a Radio Resource Control (RRC) protocol+a Physical Downlink Control Channel (PDCCH). Wherein, configuration information of the frame structure is set by an evolved Node B (eNB) in a Downlink Control Information (DCI) bit of a PDCCH sub-frame. However, during the switch of this dynamic frame structure, how to make a HARQ process of a data sub-frame be compatible with an existing HARQ timing is a problem to be solved.
In a 3GPP proposal R1-20782/20070, a HARQ method being compatible with the existing HARQ timing is given, namely: the HARQ timing of a Physical Downlink Shared Channel (PDSCH) complies with the frame structure having a maximum downlink frame proportion in candidate frame structures, and a scheduling timing of the PUSCH and the HARQ timing of the PUSCH comply with the frame structure having a maximum uplink frame proportion in the candidate frame structures.
Although the proposal R1-20782/20070 can be compatible with the existing HARQ timing, but a quantity of a HARQ process is reduced, bringing a higher transmission time delay and blocking rate, for example, when an actual frame structure 4 is adopted, while an uplink ACK/NACK (A/N) is fed back in accordance with a default frame structure 5, then the HARQ process is reduced by one time; an A/N resolution is also reduced, bringing greater performance loss, for example, when an actual frame structure 3 is adopted, while the uplink A/N is fed back in accordance with the default frame structure 5, then A/N multiplexing cannot be employed, and only an A/N bonding strategy can be employed; and unnecessary power loss is brought, for example with regards to an actual frame structure 0 and the default frame structure 5, in the actual uplink sub-frame, the UE needs to observe a downlink channel, bringing a possibility of a DCI false-alarm.